A lighting system comprising modules which are respectively provided with light source, such as solid state-based light source, e.g. light emitting diodes (so-called LED), is known from the Chinese patent application CN201661928. That document discloses a lighting system comprising a frame, a controller and a number of modules. Each module comprises a LED. A number of modules are attached to the frame. In the lighting system the controller is connected to the LEDs for driving the LEDs.
Lighting systems can be provided with LEDs. These lighting systems can be used for street lighting or other public places. Street lighting can be a demanding application for the known lighting system comprising LEDs or other solid state light sources. A lighting system for street lighting requires a quite high flux in the range of 5-25 klm and a granularity of about 2 klm. A wished total light flux of the lighting system can be obtained by adding sufficient LEDs or modules to the lighting system.
Furthermore, the conventional lighting system provided with the LEDs suffers from a decreasing light output during the lifetime due to ageing of the LEDs. In order to maintain a required minimum level of illumination level although the light output value of the individual LEDs has been degraded (e.g. 70%) from the initial value it is known to use spare LEDs besides the other LEDs used from an initial installation. These spare LEDs can be switched on and their light output controlled after a certain period of accumulated operation time of the lighting system in order to compensate for the lumen depreciation of said other LEDs. The spare LEDs makes the lighting system more expensive, in particular because the spare LEDs and their control systems are relatively expensive in comparison with to the projected price of LEDs at a point of time in the future when the spare LEDs in the lighting system will be actually used.
Moreover, these spare LEDs and associated controllers add complexity and weight to the lighting system.